Nail pulling devices



1966 l R. c. AHEARN 3,281,117

NAIL PULLING DEVICES Filed Nov. 9, 1964 2 Sheets-Sheet l R. C. AHEARN NAIL PULLING DEVICES Oct. 25, 1966 2 Sheets-Sheet 2 Filed NOV. 9, 1964 FIG.6

United States Patent 3,281,117 NAIL PULLING DEVICES Robert C. Ahearn, South Downs, Martinborough, Wellington, New Zealand Filed Nov. 9, 1964, Ser. No. 409,635 Claims priority, application New Zealand, Mar. 24, 1964, 137,702 3 Claims. (Cl. 254-26) This invention relates to nail pulling devices and has been devised particulanly though not solely for use with a carpenters claw hammer.

At present when pulling nails with a claw hammer, as the nail is extracted, the fulcrum point about which the hammer is rotated to pull the nail changes so that the leverage exerted between the fulcrum point and the nail decreases as the nail is being pulled out. It is therefore necessary when extracting the larger nails to insert a block under the hammer to restore the leverage. This is a very real disadvantage when extracting n-ails from awkward locations and also results in considerable time wastage.

It is therefore an object of the present invention to provide a nail pulling device particularly though not solely applicable to a claw hammer which will obviate or minimize the foregoing disadvantage.

Accordingly the invention consists in a nail extracting device comprising a wedging means pivotally located within a handle member, an aperture formed through the handle member and fulcrum means about which the handle may be rotated to force the wedging rneans against a nail which has been entered into the aperture to wedge the nail between a nail engaging surface of the wedging means and a wall of the aperture.

The invention will now be described with the aid of the accompanying drawings in which:

FIGURE 1 is a side view of a hammer head incorporating the nail pulling device.

FIGURE 2 is a view of the hammer head seen from the direction of the arrow 2 in FIGURE 1.

FIGURE 3 is a sectional elevation along the line A-A of FIGURE 2.

FIGURE 4 is a similar sectional view to that seen in FIGURE 3 showing the positioning of the nail in the hammer head prior to the nail being extracted.

FIGURE 5 is a further sectional elevation of the hammer head showing a nail in the process of being extracted.

FIGURE 6 is a similar view of the hammer head to that shown in FIGURE 2, but having a modified form of part of the nail pulling device.

Referring to the drawings, the hammer head which in this particular instance is one designed for use with a tubular steel handle referenced 10, has a claw 11 and a poll 12 of the usual shape. An aperture 13 is formed in the neck of the hammer head, this aperture extending through the neck in a direction approximately parallel to the axis of the handle 10, with the aperture being preferably waisted as shown in the drawings. A recess 14 is formed within the hammer head as can be seen more particularly in FIGURES 3, 4 and 5, this recess 14 being of a width slightly greater than a cam -15 which is located within the recess 14 and pivoted on a pin 16 fixed transversely within the head so that a tolerance clearance is provided between the sides of the cam 15 and the sides of the recess 14 as indicated in FIGURE 2. As can be seen in FIGURE 3, the pivot pin 16 which is the fulcrum of the cam is arranged, and the tail 17 of the cam is shaped, so that when the tail 17 is flush with the outer surface of the hammer head, then the nail engaging surface 18 of the cam 15 will have extended Patented Oct. 25, 1966 into the aperture 13 to lie adjacent to the distant wall of the aperture 13. To assist the cam 15 normally to remain in the position shown in FIGURE 3, a tension coil spring 19 has one end acnhored at 19a within the recess 14, with the other end of the spring being suitably anchored to the tail 17 of the cam 15. It is to be understood that other forms of spring means may be utilized such as a compression spring or leaf spring (not shown in the drawings) which would bear against the head of the cam in a known manner for the same purpose as the coil spring 19. Further the spring means can consist for instance of a spring which is wrapped around the cam pivot 16 with the ends of the spring appropriately looped over parts of the hammer head within the recess 14.

FIGURE 4 shows how a nail 20 can be inserted into the aperture 13 whereupon it will move the nail engaging surface 18 of the cam 15 fnom the position shown in FIGURE 3 to that of FIGURE 4. This action will pivot the cam about the pin 16 so that the tail 17 of the cam will move out of the aperture 14 as indicated in FIGURE 4. The hammer may then be moved downwardly over the nail until the tail 17 of .the cam 15 contacts the timber 21 from which the nail 20 is projecting. When the handle 10 of the hammer is moved in the direction of the arrow 3 in FIGURE 4 the tail'|17 of the cam 15 will be forced against the surface of the timber 21. The pressure exerted on the tail is then increased by the continued movement of the handle so that the nail engaging surface 18 will be forced against the side of the nail 20. Upon further movement of the handle in the direction of the arrow 3 in FIGURE 4, the pressure which is exerted on the tail 17 of the cam 15 will force the nail contacting surface 18 into further contact with the nail 20 thus wedging the nail between the nail contacting surface 18 and the side of the aperture 13. This will provide suflicient frictional resistance so that the nail is firmly gripped and may be extracted during further movement of the handle. Since the tail 17 of the cam 15 is close to the nail 20, considerable leverage is exerted on the nail. However when this leverage is lessened through an excessive change in the angle of the hammer handle 10 to the timber 21, then the hammer movement may be reversed back to the position shown in FIGURE 4 so that the nail pulling device will slide down the nail 20 towards the timber 21 and a further grip obtained if necessary.

As is shown in the figures, the wedging action of the nail engaging surface 18 can be improved by shaping the surface 18 with small corrugations, convolutions, or the like so that the surface pressure of the area in contact with the nail 20 is made as high as possible.

When using a hammer with which is incorporated the nail extracting device as previously described herein, it is possible for the tail 17 of the cam to deface the surface of the timber by making indentations thereon. However the nail pulling device will generally be employed only with the larger nails such as 4 inch and 6 inch nails which are normally used only on structural timber and not on finishing timber. However this disadvantage can be partly overcome by a reshaping of the tail of the cam (15a to that shown at 17a in FIGURE 6. This will also entail a corresponding reshaping of the aperture 14a. The larger surface area of the tail 17a will accordingly exert less pressure per square inch on the surface of the timber and so minimise any marking of such timber.

A further advantage to be obtained from the use of a hammer with the described nail pulling device is that the distance between the nail 20 and the fulcrum point of the hammer is considerably less than the distance between a nail held in the claw 11 of a hammer and the normal fulcrum of an unmodified hammer. Not only does this lessen the amount of energy required on the part of the operator to withdraw a nail but also lessens the likelihood of damage to the handle of the hammer from the use of excessive force.

Apart from use in extracting nails, because of the particular construction of the nail extracting device, it can also be used in fence wire straining Where the operating principle is as above described for nail pulling. It will also be obvious that the device can be used in any other operation wherein it is desired to tension a wire provided the wire is of a diameter that can be passed through the aperture 13 and gripped by the nail extracting surface 18.

I claim:

1. A nail-extracting device for use with a hammer having a main body portion and a poll integral therewith and with a bottom surface, wherein there is an aperture between said main body portion and said poll in which the projecting portion of a nail may be positioned, and wherein said main body portion has a recess connected to said aperture, wedging means positioned within said recess and having two end portions one of which is a wedge portion and is adapted to rest against the side of a nail positioned within said aperture and to urge the nail against the side wall of said aperture, pivot means pivotally mounting said wedging means to swing with respect to said main body portion about an axis which is between said two end portions from a rest position toward a displaced position, the other of said end por tions being a lever portion and being positionedbetween said axis and the bottom surface of said main body portion, said lever portion having an outside surface which is at said bottom surface of said main body portion when said wedging means is in said rest position and which is moved outwardly away from said recess when said wedging means is moved towards said displaced position by the positioning of a nail in said aperture whereby said lever portion projects from said main body portion and forms a fulcrum about which said main body portion may be swung with said Wedging means transmitting force from said lever portion to the other side of said axis and through said cam portion to clamp the nail against said side wall while simultaneously drawing the nail upwardly.

2. A nail-extracting device as described in claim 1 which includes a coil spring mounted between said wedging means and said main body portion and urging said wedging means towards its rest position.

3. A nail-extracting device as described in claim 1, wherein said pivot means is a pin mounted in said main body portion and wherein said cam portion has a plurality of corrugations which are adapted to engage a nail in said aperture.

References Cited by the Examiner UNITED STATES PATENTS 149,912 4/1874 Bilharz 254-22 832,387 10/1906 Jensen 25422 2,922,622 1/1960 Ralston et al. 25426 WILLIAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examiner. 

1. A NAIL-EXTRACTING DEVICE FOR USE WITH A HAMMER HAVING A MAIN BODY PORTION AND A POLL INTEGRAL THEREWITH AND WITH A BOTTOM SURFACE, WHEREIN THERE IS AN APERTURE BETWEEN SAID MAIN BODY PORTION AND SAID POLL IN WHICH THE PROJECTING PORTION OF A NAIL MAY BE POSITIONED, AND WHEREIN SAID MAIN BODY PORTION HAS A RECESS CONNECTED TO SAID APERTURE, WEDGING MEANS POSITIONED WITHIN SAID RECESS AND HAVING TWO END PORTIONS ONE OF WHICH IS A WEDGE PORTION AND IS ADAPTED TO REST AGAINST THE SIDE OF A NAIL POSITIONED WITHIN SAID APERTURE AND TO URGE THE NAIL AGAINST THE SIDE WALL OF SAID APERTURE, PIVOT MEANS PIVOTALLY MOUNTING SAID WEDGING MEANS TO SWING WITH RESPECT TO SAID MAIN BODY PORTION ABOUT AN AXIS WHICH IS BETWEEN SAID TWO END PORTIONS FROM A REST POSITION TOWARD A DISPLACED POSITION, THE OTHER OF SAID END PORTIONS BEING A LEVER PORTION AND BEING POSITIONED BETWEEN SAID AXIS AND THE BOTTOM SURFACE OF SAID MAIN BODY PORTION, SAID LEVER PORTION HAVING AN OUTSIDE SURFACE WHICH IS AT SAID BOTTOM SURFACE OF SAID MAIN BODY PORTION WHEN SAID WEDGING MEANS IS IN SAID REST POSITION AND WHICH IS MOVED OUTWARDLY AWAY FROM SAID RECESS WHEN SAID WEDGING MEANS IS MOVED TOWARDS SAID DISPLACED POSITION BY THE POSITIONING OF A NAIL IN SAID APERTURE WHEREBY SAID LEVER PORTION PROJECTS FROM SAID MAIN BODY PORTION AND FORMS A FULCRUM ABOUT WHICH SAID MAIN BODY PORTION MAY BE SWUNG WITH SAID WEDGING MEANS TRANSMITTING FORCE FROM SAID LEVER PORTION TO THE OTHER SIDE OF SAID AXIS AND THROUGH SAID CAM PORTION OF CLAMP THE NAIL AGAINST SAID SIDE WALL WHILE SIMULTANEOUSLY DRAWING THE NAIL UPWARDLY. 